For example, in a semiconductor manufacturing apparatus or facility, and in a gas pipe such as a ¼″ pipe, a ⅜″ pipe or a ½″ pipe, there can occur a case where a reactive gas or liquid flowing through the inside is condensed and clogging occurs. As countermeasures against that, the pipe is heated and is kept at a specified temperature. Besides, also in order to cause the heated gas or liquid to flow while the high temperature state is kept, the pipe is heated.
As a heating method of a pipe, in order to uniformly heat the pipe, there is generally adopted a method in which a metal surrounding body such as a cylindrical aluminum block is attached to the pipe, and this surrounding body is heated to indirectly heat the pipe. As a covering body for heating a pipe used for such heating, there is known one having such a structure that surrounding bodies such as semi-cylindrical aluminum blocks are fitted to a pipe, and the surrounding bodies are screwed to each other and are held on the pipe. However, in this covering body for heating a pipe, since the screw hole is required to have accuracy to a certain degree, the working cost of the surrounding body becomes high. Further, since plural places must be screwed, the work requires much time, and the screwing work in a narrow space becomes difficult. Further, according to the degree of tightening by the screwing, the inner wall of the surrounding body does not come in uniform contact with the pipe, and the skill is required to a certain degree.
Besides, there is also known a covering body for heating a pipe having such a structure that a cylinder is divided into plural parts, a surrounding body with many concave grooves formed along an axial direction on an outer peripheral surface is fitted to a pipe, and both ends of a fitting body made of a semicircular spring member are fitted in the concave grooves of the surrounding body so that the surrounding body is attached to the pipe and is held (see reference 1). In this covering body for heating a pipe, the workability is good, the fitting body can be easily attached to the surrounding body even in a narrow space, and unevenness disappears in the holding state.
[Reference 1] JP-A-2003-185086
In general, in a semiconductor manufacturing apparatus or facility, the maintenance of a pipe is periodically performed, and at that time, it is necessary to remove a covering body for heating a pipe. Although the covering body for heating a pipe of the reference 1 is excellent in the attachment property of the fitting body as stated above, both ends of the fitting body are firmly fitted in the concave grooves of the surrounding body so that the fitting body does not easily come off from the surrounding body. Thus, it takes much labor to remove the fitting body from the surrounding body.
In order to remove the fitting body, there is a method in which a paddle-shaped tool is inserted between the fitting body and the surrounding body, and the fitting body is pressed up by the principle of leverage. However, the surrounding body is generally an aluminum block, and when the tool is inserted or pressed up, the surface is likely to be damaged and aluminum powder is likely to be generated. In the semiconductor manufacturing apparatus or facility, high-level clearness is required, and the pollution by the aluminum powder becomes a serious problem.